Harsha COMMUNICATIONS

Multivibrator: Multivibrator discover their own space in lots of applications as they are among the most broadly used circuits. The application can be anyone either a household application or industrial or communication, etc. The multivibrator can also work in such type of application either as an oscillator or digital flip flop or pulse generator circuit or like a timer or I can be lay generator circuit and lots more. There are mainly three types of Multivibrators. They are Astable Multivibrator: It has actually no stable state. It has two quasi steady state which rapidly alters from one to another and again to the same state. So it’s mainly alters from high to low and from low to high devoid of any input trigger input after pre settled time. Monostable multivibrator: Out of two states, one is stable state and another one is quasi state. When trigger input is given, it switches from a stable state of quasi state. And it automatically switches to a stable state ...

This circuit alerts us when there is a fire accident at home by ringing a siren sound . You might have seen fire alarms earlier but this is quite different as it generates a siren sound instead of a buzzer and also it uses basic components to generate that siren sound. We are aware that there are many integrated circuits which can be used to generate the siren effect but we preferred to use basic electronics components like resistors, capacitors and transistors to generate it so that you will clearly understand the internal working of it and it will be much useful for you as you will gain more knowledge by analyzing it instead of simply going or pre designed integrated circuits. Circuit Diagram of Fire Alarm: Description: This circuit uses a thermistor to sense the temperature. When it senses that the temperature of the environment is increasing above a given threshold, then it gives a signal. The temperature at which the circuit detects fire can be adjusted ...

The main aim of this project is to operate and control the unmanned railway gate in the proper manner in order to avoid the accidents in the unmanned railway crossing. In a country like ours where there are many unmanned railway crossings, accidents are increasing day by day. These train accidents are due to the absence of human power in the railway. In order to overcome the accidents due to the above problem we have planned to design the project. Automatic Railway Gate Control System with High Speed Alerting System is an innovative circuit which automatically controls the operation of railway gates detecting the arrival and departure of trains at the gate. It has detectors at the far away distance on the railway track which allows us to know the arrival and departure of the train. These detectors are given to microcontroller which activates the motors which open/close the railway gate correspondingly. Another feature of this circuit is that it has an intellige...

Circuit Diagram of Automatic Door Bell Using Object Detection: This circuit operates using a pair of ultrasonic transmitter and receiver modules which are used to detect the person and then if the person is detected, the door bell is automatically turned ON when the person is in-front of the door. The ultrasonic transmitter operates at a frequency of about 40 Kilo-Hertz. That means it continuously transmits the ultrasonic waves of about 40KHz. The power supply should be moderate such that the range of the transmitter is only about one or two meters. If the transmitting power is less than one meter, then there is a chance that the person who is one meter away is not detected. Also, if the range is set to be very large, then it may lead to false triggering, meaning that, the objects far away from our door are considered as the visitors and the alarm rings. This can be a nuisance for us if the alarm rings for every object or person far away. So, to avoid both the ...

Simple Mobile Jammer Circuit Diagram: Simple Mobile Jammer Circuit Diagram Cell Phone Jammer Circuit Explanation: If you understand the above circuit, this circuit analysis is simple and easy. For any jammer circuit, remember that there are three main important circuits. When they are combined together, the output of that circuit will work as a jammer. The three circuits are RF amplifier. Voltage controlled oscillator. Tuning circuit. So the transistor Q1, capacitors C4 & C5 and resistor R1 constitute the RF amplifier circuit. This will amplify the signal generated by the tuned circuit. The amplification signal is given to the antenna through C6 capacitor. Capacitor C6 will remove the DC and allow only the AC signal which is transmitted in the air. When the transistor Q1 is turned ON, the tuned circuit at the collector will get turned ON. The tuned circuit consists of capacitor C1 and inductor L1. This tuned circuit will act as an oscillator with zero resi...

Introduction: While parking the car the driver should be more careful because he cannot see the back of the car while parking or taking reverse, if there is any obstacle and ran over it might be  get damage to the car. Our project will help the person in the driving seat and give alarm if there is any obstacle or a wall while parking or while driving in reverse. Block Diagram of Car Parking Guard: The IR sensor will detect the obstacle with in 100cm, if there is any obstacle it will sense and give information to the tone detector which will enable the LM555 timer to generate a PWM for the buzzer. The LM555 will generate the pulse which helps to buzz the buzzer so driver can understand that there is an obstacle. Main Component Explanation: LM567: is a tone detector which can interpret the frequency generated by the other component and give the output according to the application designed by the engineer. For example if a component is attached to the input o...

Generally appliances that we used in our home are being controlled with the  help of devices like switches, senors. However sometimes it is dangerous to have physical contact with these switches. So to overcome these dangers, here we have explained a circuit that needs no physical contact with the appliance. In these circuits all you  need is to pass your hand  above LDR. As you first pass your hand over LDR the device connected with  it started and remain in that state till you again pass your hand above LDR. These circuits are mainly depending on two ICs. First one is LM714 which is an operational amplifier. These IC is used to increase the voltage level at the output hundred  of a thousand times as compared with  the input. Another one is most generally used JK flip flop i.e. CD4027. These IC works in toggle mode and based on the JK flip flop master slave concept. This IC is used to alter the state when the signal is given to the any one...